PRETREATMENT OF WHEAT STRAW IN DEEP EUTECTIC SOLVENT MEDIUM FOR ENZYMATIC HYDROLYSIS ENHANCEMENT

The results of the study presented the possibility of using deep eutectic solvent based on triethylamine hydrochloride as a method of preliminary treatment of wheat straw for enzymatic hydrolysis. Thermal treatment in triethylamine hydrochloride / oxalic acid medium was conducted in the temperature range 80–110 °С. Fractionation of the products mixture allowed to isolate cellulose, hemicelluloses and lignin fractions. The results of composition analysis as well as IR-spectra of technical cellulose indicate the intensive processes of delignification and hemicellulose hydrolysis during the treatment. The maximum degree of delignification (94.5%) was obtained at the temperature of 110 °C, while total cellulose content in the technical cellulose was 91.2% dry mass. It was found that treatment of wheat straw in triethylamine hydrochloride / oxalic acid medium is efficient as a preparation step for enzymatic hydrolysis. The maximum yield of reducing sugars (27% dry mass) was achieved by 48 h enzymatic hydrolysis of technical cellulose, isolated at 110 °C, which is three times higher than the yield of sugars from untreated straw.